An electrical vehicle, a hybrid vehicle or the like is provided with a maintenance electric connector (so-called a service plug). Usually, a plug connector is plugged into a receptacle connector. For maintenance of an electric system of the vehicle, the plug connector is removed from the receptacle connector, so that current from a battery can be shut off. As such an electric connector, Patent Literature 1 discloses an electric connector including a socket connector having an insertion hole and a plug connector having a bar shape, the plug connector arranged to be capable of being inserted to and removable from the insertion hole of the socket connector and to be rotatable between a unlocked position and a locked position about an axis thereof.
This electric connector further includes, as a means for detecting the locked state of the plug connector with respect to the socket connector, a conductor portion partially provided on the circumferential surface of the plug connector and a pair of detection terminals that are disposed in the insertion hole and can contact the conductive member (conductor portion) of the plug connector. When the plug connector is locked to the socket connector, the conductive member contacts the pair of detection terminals, the state being locked is detected, and current flows into a main circuit. In contrast, when the locking is released, the conductive member moves away from the pair of detection terminals, the release of locking is detected, and the current to the main circuit is shut off.